.container {
    height: 700px;
    border: 1px solid #eee;
    display: flex;
    flex-direction: column;
}

.header {
    flex: 0 0 auto;
}

.content {
    flex: 1 1 auto;
    display: flex;
}

.aside {
    /*flex: 0 0 25%;*/
}

.main {
    flex: 1 1 auto;
}
